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Y Tamai

Publications and source records attributed to Y Tamai.

At least 127 records · Page 7Linked to original sources
PubMed1993

Sequence specific binding of Ets-1 to the mouse cytokeratin EndoA gene enhancer.

Expression of the mouse cytokeratin EndoA gene is regulated by an enhancer that is located 1 kilobases (kb) 3' downstream from the gene. The EndoA enhancer consists of six direct repeats with homology to the PEA3 motif in the polyoma virus enhancer core. The PEA3 motif binds to the proto-oncogene Ets product. In this report we show that GST-c-Ets-1 fusion protein binds specifically to the EndoA enhancer unit sequence by gel shift analysis. Footprinting showed that the Ets-1 binding site consisted of 20 bases in each repeat. Ets-1 also moderately activated the EndoA enhancer. These results demonstrate that Ets-1 binds in a sequence specific fashion to the mouse EndoA enhancer and suggest that c-Ets-1 or other related Ets family genes function in regulating EndoA gene expression.

Animals↗
PubMed1993

Principal neurons as local circuit neurons in the rat superior cervical ganglion: the synaptology of the neuronal processes revealed by intracellular injection of biocytin.

To analyze the local circuitry of the sympathetic ganglion, the synaptic relations of the neuronal processes of the principal neurons in the rat superior cervical ganglion were investigated by correlated light and electron microscopy combined with intracellular injection of biocytin. Intracellular iontophoresis of biocytin followed by avidin-biotinylated horseradish peroxidase cytochemistry allowed complete visualization of the neuronal processes of the principal neurons. The stained principal neurons have a single process (axon), which leaves the ganglion, and several intraganglionic processes (dendrites), some of which show specific terminal arborizations. Some terminals of the dendritic collaterals formed pericellular plexuses or intercellular glomerular plexuses. Electron microscopically, the dendrites and their collaterals contain numerous small vesicles. Synaptic membrane specializations were observed between the stained dendritic collaterals and unlabeled neurites. These may be both preganglionic axon terminals and processes of principal neurons. The likely direction of neurotransmission often could not be determined because of the bidirectional synaptic structures. Our findings show that the dendritic collaterals of principal neurons appear to make both post- and presynaptic contacts with both the principal neurons and the preganglionic axons. It is suggested that the principal neurons might participate in local circuits involving not only preganglionic axons but also neighboring principal neurons.

Animals↗
PubMed1993

Characterization of plasma membrane H(+)-ATPase from salt-tolerant yeast Candida versatilis.

Plasma membrane was isolated from the salt-tolerant yeast Candida versatilis and the ATPase in plasma membrane was characterized. The ATPase was a typical H(+)-ATPase with similar properties to the Saccharomyces cerevisiae and Zygosaccharomyces rouxii enzymes. It was reacted with antibody (IgG) raised against S. cerevisiae plasma membrane H(+)-ATPase. The ATPase activity was not changed by adding NaCl and KCl to the assay solutions, but was increased by NH4+, especially by ammonium sulfate. In vivo stimulation of ATPase activity was observed by the addition of NaCl into the culture medium, as observed in Z. rouxii. No in vivo activation of H(+)-ATPase by glucose metabolism was observed in C. versatilis cells and the activity was independent of the growth phase, like Z. rouxii and unlike S. cerevisiae cells.

Azides↗
PubMed1993

Experiments on maternal and paternal transmission of Creutzfeldt-Jakob disease in mice.

No transmission of Creutzfeldt-Jakob disease in mice was observed in 75 offspring born to CJD agent-inoculated females or to normal females mated with inoculated males and in 19 normal offspring maintained by foster nursing with the inoculated mothers. The fertility of young adult female mice was lost by the 57th day after the inoculation, whereas the reproductivity of male mice was maintained over 106 days after the inoculation.

Aging↗
PubMed1993

A missense mutation in type VII collagen in two affected siblings with recessive dystrophic epidermolysis bullosa.

Recessive dystrophic epidermolysis bullosa is a severe mutilating genodermatosis. Previous ultrastructural demonstrations of altered anchoring fibrils, and recent genetic linkage analyses have suggested that type VII collagen, the major component of anchoring fibrils, is a candidate gene. We have identified a homozygous methionine-to-lysine mutation in two affected siblings, while their unaffected mother and half-brother are heterozygous carriers. The mutation resides in a highly conserved region of the C-terminus of type VII collagen, strongly suggesting that it is the cause of the disease in this family.

Amino Acid Sequence↗
PubMed1993

Isolation of a subclonal cell line of PC12 transfected with dexamethasone-regulated ras oncogene: morphological differentiation, biochemical properties, and tumorigenicity.

We have isolated and characterized a new subclonal cell line designated as MR31, which was obtained by transfection of PC12 cells with a glucocorticoid-regulated ras oncogene. The mRNA derived from the c-Ha-ras gene was proved to be expressed on exposure of the MR31 cells to dexamethasone, the highest value being attained at 8 h. MR31 cells rapidly extended neurite-like processes within 24 h in response to dexamethasone as well as nerve growth factor (NGF). The time of onset of neurite outgrowth induced by dexamethasone corresponded to the time when the highest ras mRNA level was observed. The catecholamine content of MR31 cells was found to be twice that of PC12 cells. A time course study on the effects of dexamethasone or NGF on cells showed that the former caused an increase in dopamine, a major catecholamine, to twofold the control level at 48 h after the treatment, while the latter caused a decrease in the dopamine level. These effects on catecholamines were almost the same in MR31 and PC12 cells. The acetylcholinesterase activity of MR31 cells was enhanced by both dexamethasone and NGF, whereas that of PC12 cells was enhanced by NGF, but not by dexamethasone. The changes in acetylcholinesterase activity were correlated with neurite outgrowth. Electron-microscopically, MR31 cells were not different from PC12 cells. MR31 cells exhibited extremely decreased tumorigenicity as compared with PC12 cells. The morphological and biochemical properties of MR31 cells remained constant, even after repeated passages.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Calcium ion dependent interaction of inorganic phosphorus compounds with phosphatidylcholine.

The translocation of orthophosphate, pyrophosphate, and polyphosphate into an organic phase was examined by means of the two-phase partition method. When the organic phase contained phosphatidylcholine (PtdCho), the phosphorus compounds translocated from the water-phase into the organic phase, depending on the concentrations of PtdCho and Ca2+, and the pH of the solution. Calcium ions were essential for the translocation. The concentration of Ca2+ necessary for the translocation appeared to depend on the molar concentration of the phosphorus compounds. Orthophosphate was translocated above pH 6.5, while pyrophosphate was translocated above pH 3.5. In contrast, polyphosphate was translocated in the whole pH range examined (pH 2.5-9.0), although approx. 9% of the total polyphosphate remained in the water-phase even at alkaline pH. These results suggest that phosphorus compounds can interact with PtdCho when the phosphorus compounds have formed complexes with Ca2+.

Calcium↗
PubMed1993

A novel fucosylated glycosphingolipid with a Gal beta 1-4Glc beta 1-3Gal sequence in plerocercoids of the parasite, Spirometra erinacei.

A novel glycosphingolipid (SEGLx) has been isolated from the plerocercoids of a tapeworm, Spirometra erinacei. From the results of compositional analysis, methylation analysis, exoglycosidase hydrolysis, acid hydrolysis, fast atom bombardment mass spectrometry, and proton nuclear magnetic resonance (NMR) analysis, its structure was concluded to be [formula: see text] This is the first report of a glycosphingolipid with a novel carbohydrate structure which is characterized by i) the occurrence of a penultimate glucose molecule attached to the reducing end galactose through a beta 1-3 linkage and ii) the presence of a fucose attached to a glucose through an alpha 1-3 linkage. The ceramide contained sphinganine or 4-D-hydroxy-sphinganine, and either a nonhydroxy fatty acid with 16, 18, 26, or 28 carbon atoms, or hydroxystearic acid. Proton NMR analysis revealed that the chemical species of both the long chain base and fatty acid moieties affect the chemical shifts of the anomeric proton resonances of not only the reducing terminal galactose but also the penultimate glucose.

Animals↗
PubMed1993

Metamorphic changes in glycolipids and myelin proteins and 2',3'-cyclic nucleotide 3'-phosphohydrolase in bullfrog and axolotl brains.

The metamorphic changes in levels of glycolipids and myelin proteins and 2',3'-cyclic nucleotide 3'-phosphohydrolase (CNP) in the brains of bullfrog tadpoles, adult frogs, and axolotls were investigated, with particular emphasis on myelin maturation. The concentrations of cerebroside, sulfatide, and galactosyldiacylglycerol gradually increased from the onset of prometamorphosis throughout the active metamorphic period and then greatly increased after metamorphosis was completed. The ratio of glucocerebroside to galactocerebroside increased greatly in the prometamorphic period and then rapidly decreased to the frog level during the climax period. The fatty acid compositions of cerebroside and sulfatide showed a developmental change, with 24:1 being more predominant in the later metamorphic stage. The proportion of hydroxy fatty acids increased up to the onset of the prometamorphic stage and thereafter remained constant at approximately 50% of the total. The CNP activity remained unchanged throughout metamorphosis at 60% that in frog myelin and increased in the adult frog. The composition of tadpole myelin proteins remained constant during metamorphosis, with large basic protein being the most abundant, and in the frog, proteolipid protein and large basic protein were present in comparable amounts. The two adult forms of axolotl, i.e., the neotenous and metamorphosed forms, exhibited almost identical myelin constituents, and CNP activity in the neotenous form amounted to one-fifth that in the bullfrog. These results indicate that active biosynthesis of myelin marker components occurs as metamorphosis proceeds, but more pronounced changes of myelin components occur after metamorphosis is completed.

2',3'-Cyclic Nucleotide 3'-Phosphodiesterase↗
PubMed1993

The human 230-kD bullous pemphigoid antigen gene (BPAG1). Exon-intron organization and identification of regulatory tissue specific elements in the promoter region.

The 230-kD bullous pemphigoid antigen (BPAG1), a hemidesmosomal protein, is encoded by a gene at the human chromosomal locus 6p11-12. We have elucidated the exon-intron organization of the entire human BPAG1 gene, including approximately 2.6 kb of 5'-flanking DNA. Seven overlapping genomic clones, spanning approximately 20 kb, contained the entire approximately 9 kb coding sequence of BPAG1 and consisted of 22 separate exons, which varied from 78 to 2,810 bp in size. The 5' flanking region of DNA, upstream from the ATG initiation codon for translation, was found to contain several putative transcriptional response elements. Most interestingly, two motifs potentially conferring keratinocyte specific expression to the gene were detected. The presence of such elements was suggested by approximately 20-fold higher expression of a promoter/chloramphenicol acetyl transferase (CAT) construct in normal human epidermal keratinocytes that express the endogenous gene, as compared to several non-expressing cell types. Transient transfections with 5'-deletion clones of the promoter/reporter gene (CAT) constructs identified a region containing a putative tissue specific element, KRE2, which also conferred tissue specificity to the expression of the truncated promoter downstream from this element, however, a mutated derivative of KRE2 was not functional. Detailed knowledge of the structure and regulation of the BPAG1 gene will aid in further elucidation of diseases affecting the cutaneous basement membrane zone.

3T3 Cells↗
PubMed1993

[Synthesis and antiulcer effects of 5-hydroxy-4-[2-substituted-(E)-ethenyl]-2(5H)-furanone. (1)].

gamma-Hydroxybutenolides possessing conjugated substituents at the beta-position and their related compounds have been synthesized by the previously reported procedure with minor modifications and their antiulcer activities have been examined in the HCl-ethanol induced ulcer model often used for the evaluation of gastric mucosal protective factor enhancing effect. The compound A-1 5-hydroxy-4-[2-(2,6,6-trimethyl-1-cycohexenyl-1-yl)-(E)-ethenyl]-2 (5H)-furanone showed a pronounced effect at a low dosage of 5 mg/kg p.o. and some analogues compounds also exhibited potent inhibitory activity as compared with the reference drugs. The relationship between the structure of gamma-hydroxybutenolides and the antiulcer effect has been also examined and then the 5-hydroxyl group has been found to be essentially functional one to have antiulcer activity.

4-Butyrolactone↗
PubMed1993

[Hemophilia A complicated with hepatocellular carcinoma].

A 60-year-old hemophiliac man complaining of abdominal discomfort was admitted on suspicion of hepatocellular carcinoma (HCC) by ultrasonography (US). When he was 22-year-old, blood transfusion was given for intra-abdominal hematoma due to an external wound and a diagnosis of moderate hemophilia A and non-A non-B type chronic hepatitis (later, C type chronic hepatitis) was made at the age of 40. After admission, HCC in the S6 segment of the liver was diagnosed by US, computerized tomography, magnetic resonance imaging and angiography. He was treated with transcatheter arterial embolization (TAE) and partial resection of the liver. Later, percutaneous ethanol injection therapy and TAE was performed because of the recurrence of HCC. He is now alive with no evidence of recurrence. The rate of infection with hepatitis C virus (HCV) is significantly high in hemophiliacs but, because of the replacement therapy, their life expectation has dramatically improved in last two decades. Therefore, it is speculated that the incidence of HCC in hemophiliacs will increase. We emphasize that regular US examination for HCV-positive hemophiliacs is important for the early detection of HCC.

Carcinoma, Hepatocellular↗
PubMed1993

Less polar glycolipids in Alaskan pollack brain: isolation and characterization of acyl galactosyl diacylglycerol, acyl galactosyl ceramide, and acyl glucosyl ceramide.

We recently reported that glycolipid compositions of gadoid fish nerve tissues are unique in the abundance of 1) galactosyl diacylglycerol and its sulfate ester; 2) glucosyl ceramide; and 3) fatty acid ester of cerebroside (J. Lipid Res. 1992. 33: 1351-1359). The present paper reports the characterization of less polar glycolipids isolated from Alaskan pollack brain. Of twelve glycolipids purified by column chromatography, four were of the galactosyl diacylglycerol type. Chemical analysis, infrared spectrometry, and a permethylation study followed by gas chromatography-mass spectrometry revealed that they were 1,2-di-O-acyl-3-beta (6-O-acyl-D-galactopyranosyl)-sn-glycerol and 1,2-di-O-acyl-3-beta(2'-O-acyl-D-galactopyranosyl)-sn-glycerol, and mixtures of these two isomers, with slightly different fatty acid compositions, respectively. The other eight less polar glycolipids were pure forms or mixtures of isomeric forms of cerebroside fatty acid esters in which the substituted position of the acyl group on the hexose moiety varied. The permethylation study revealed that they were 6-O-acyl-beta-D-galactopyranosyl, 6-O-acyl-beta-D-glucopyranosyl, 2-O-acyl-galactosyl, 2-O-acyl-glucosyl, 3- or 4-O-acyl-galactosyl, and 3-O-acyl-glucosyl ceramides, the 6-O- and 2-O-acyl isomers being predominant. This is the first report of the natural occurrence of 1) acyl galactosyl diacylglycerol in animal tissues and 2) acyl glucosyl ceramide in nerve tissues.

Animals↗
PubMed1992

Inhibitory effect of 5-hydroxy-4-(2-phenyl-(E)-ethenyl)-2(5H)-furanone, a novel synthesized retinoid, on azoxymethane-induced intestinal carcinogenesis in rats.

Modifying effects of 5-hydroxy-4-(2-phenyl-(E)-ethenyl)-2(5H)-furanone, a novel synthesized retinoid (KYN-54), on intestinal carcinogenesis were examined in a rat model using azoxymethane (AOM). A total of ninety male F344 rats, 6 weeks old, were divided into 4 groups. Group 1 (20 rats) was fed a diet containing KYN-54 at a concentration of 0.02% for 3 weeks, during which time 2 s.c. injections of azoxymethane (15 mg/kg) were applied and then kept on a basal diet until the end of the experiment (1 year). Group 2 (30 rats) was given azoxymethane as in group 1 and fed the basal diet throughout, without synthetic retinoid exposure. Group 3 (20 rats) was administered KYN-54 at the commencement of the experiment, but not given the carcinogen. Group 4 (20 rats) received a basal diet alone throughout the experiment and served as a control. Intestinal tumors were seen in groups 1 and 2, their incidence and average number in group 1 (74%, 1.07 +/- 0.87) being significantly less than in group 2 (39%, 0.56 +/- 0.78) (P < 0.02 and P < 0.05, respectively). These results suggest that the synthetic retinoid might be a promising chemopreventive agent for intestinal neoplasia.

4-Butyrolactone↗
PubMed1992

Sensory response of cortical neurons in the anterior ectosylvian sulcus, including the area evoking eye movement.

The deep cortical tissue in the caudal portion of the anterior ectosylvian sulcus (AES) of cats anesthetized with alpha-chloralose was explored to examine the sensory response properties of neurons in this area, which is known to contain an area evoking eye movement. Of 873 neurons isolated, 262 (30.0%) were multimodal, i.e. responsive to two or more of the stimulus modalities of visual, auditory, or somatic. The ratio of multimodal neurons to total neurons in the eye-movement-evoking area was significantly larger than this ratio in other areas; 79 (39.5%) of 200 neurons in the eye-movement-evoking area were multimodal, while 183 (27.2%) of 673 neurons in other areas were multimodal. Neuronal minimal latency in response to visual stimulation was widely and bimodally distributed, showing two peaks at 35 ms and 60 ms, whereas latencies to auditory and somatic stimulation were narrowly distributed, with one peak at 10 ms and 15 ms, respectively. There was no remarkable difference either between unimodal neurons and multimodal neurons or between the neurons in the eye-movement-evoking area and those in other areas in distribution of latency. That there was a significant difference in ratio of multimodal to total neurons between the eye movement area and other areas suggests that some convergence or integration of different kinds of sensory input in relation to eye movement might be carried out in the caudal portion of the AES.

Animals↗
PubMed1992

Postremission therapy without prednisolone improves survival in adults with acute leukemia.

This prospective randomized clinical trial was to clarify whether postremission therapy without prednisolone (PSL) was more effective than therapy with PSL in improving the 5-year survival of adults with acute leukemia. Thirty consecutive adult patients with newly achieved complete remission were randomized to receive postremission therapy either with or without PSL between September 1985 and September 1988. The patients ranged from 16 to 57 years in age. Patients treated without PSL had a significantly better 5-year survival rate than those receiving PSL according to Kaplan-Meier analysis (53.5% vs 15.3%, p < 0.05). In the group treated without PSL, eight out of 15 patients were alive at 72 months, and seven patients maintained their first complete remission at 72 months. Among patients with acute lymphoblastic leukemia (ALL) who were treated without PSL the median duration of remission was 24 months, and the survival rate at 72 months was 50.0%. On the other hand, the median survival was only 13 months for the 5 patients with ALL treated with PSL. Thus, it is desirable that adults with acute leukemia are treated by postremission therapy without PSL.

Acute Disease↗
PubMed1992

Characteristic distribution of glycolipids in gadoid fish nerve tissues and its bearing on phylogeny.

Glycolipids were isolated from nerve tissues of gadoid fishes including Alaskan pollack and Pacific cod. Their chemical structures were determined by gas-liquid chromatography and gas chromatography-mass spectrometry, and their constituents were analyzed in detail and compared with those of glycolipids from other fish groups. The results revealed that gadoid fish nerve membranes contain peculiar glycolipid molecular species that are distinctly different from those in other teleostean fishes and higher vertebrates. The mole percentage ratio of the four major glycolipids (cerebroside-sulfatide-galactosylglyceride-sulfogalactosylglyce ride) was 48:12:25:15, indicating profound accumulation of glycoglycerolipids. Galactosylglyceride and sulfogalactosylglyceride were primarily of the diacyl type (greater than 90%), the major fatty acids being 16:0 and 18:1. An abundance of glucocerebroside (25 to 55% of cerebroside) and its fatty acid ester (37 to 47% of ester cerebroside) was noted. Cerebroside and sulfatide were characterized by the absence of hydroxy and odd numbered fatty acids, and 24:1 acid was a predominant component of both glucocerebroside and galactocerebroside. Subcellular fractionation revealed that myelin membranes comprised such unusual glycolipid constituents as those seen in whole nerve tissues. A vertebrate whose nerve membranes consist of such peculiar glycolipid molecules has not previously been reported. The characteristics of the glycolipid composition in gadoid fishes are discussed in relation to myelin functions, physicochemical properties of nerve membranes, and the phylogenic significance of this fish group.

Animals↗